The objective of the Human Population Laboratory is to uncover heretofore unobserved relationships between social, psychological and physical patterns of living and states of individual health. A probability sample of 6,928 Alameda County residents has been selected. From this population, the Laboratory seeks to: 1. provide estimates of disability and social maladaptation for Alameda County; 2. explore the relationship between disease and disability on the one hand and psychological traits, social and familial background, physical patterns of living and demographic characteristics on the other; 3. examine the relationship between physical health and "social health"; 4. observe the early stages of development of ill health and the social, psychological and environmental changes which may accompany it; 5. relate changes in individual levels of health between two points in time to ways of living, to utilization of health services, and to intervening stresses and life style; 6. contribute to the methodology of survey research by testing the reliability and validity of health information collected by questionnaire. Through a program of cross-sectional trend surveys the Laboratory will investigate the utilization of and consumer attitudes about existing health facilities, and will explore areas of unmet need for new services as part of a general surveillance of health care delivery systems.